UV light may have sparked life on Earth

NewScientist.com ^ | May 28, 2003

[StupidQuestions]

UV light may have sparked life on Earth

18:18 28 May 03

NewScientist.com news service

Ultra-violet light, long thought to be an impediment to the early formation of long organic molecules, may in fact hold the key to the origin of life, according to a new study.

Intense UV rays from a young Sun bombarded the early Earth and were thought likely to destroy any exposed organic molecules. But a new mathematical model implies the radiation actually helped select out the molecular seeds of life.

The earliest life on Earth is widely thought to have been based on RNA, the chemical cousin of DNA. RNA is made of subunits called nucleotides, which link together to form long polymer chains.

Certain components of RNA absorb UV light and act as "protectors", thereby giving it a survival advantage over other molecules, says Armen Mulkidjanian. Mulkidjanian, a biophysicist at Osnabrück University in Germany, led the team that developed the theoretical model.

"Simple RNA molecules can evolve under certain conditions - this is a well-developed field. But the question left is: how do you get the first long enough RNA polymer?" says Mulkidjanian. "Our model offers some physically plausible explanation of how long RNA polymers could emerge."

"This paper is important because it attacks that crucial problem," says Michael Yarus, an RNA world expert at the University of Colorado at Boulder. "If this problem could really be solved in a way that people agreed on, the RNA world would become a fact rather than a speculation."

Peculiar properties

Life on Earth is thought to have evolved about 3.7 billion years ago, when there was no protective ozone layer encasing the planet and UV radiation was 100 times more intense than today.

The nucleotides that make up RNA have three components - a sugar, a phosphate and nitrogen-containing base. "And these bases have very peculiar properties of being extremely efficient at quenching UV light," says Mulkidjanian, protecting the sugar and phosphate components which form the spine of the chain.

The team fed data on the photochemistry of various organic molecules into a computer model designed to simulate the effects of UV light on stability. "The effect was very pronounced in RNA," he says. In the presence of strong UV light, RNA was much more likely to form long chains than other molecules. -more-

[Scenic Sounds]

Intense UV rays from a young Sun bombarded the early Earth and were thought likely to destroy any exposed organic molecules. But a new mathematical model implies the radiation actually helped select out the molecular seeds of life.

Amelia, Amelia!! You were right! You were right!

You were right all along!!

[Kudsman]

Pasteur never proved (and never attempted to prove) anything about the ultimate origin of life on earth.

Okay. So who has and where is it recorded? I would like to read it. Mr. Pasteur never disproved the existence of I AM THAT I AM either. Did he? I'm not asking to be facetious, I really am not familiar with all his experiments.

[dljordan]

It sure sparked plenty of new life back in the 60's.

[tortoise]

I don't believe that you can apply natural selection to chemicals.

??? Sure you can. There is some arbitrary number of pathways a chemical reaction can take, but depending on the local conditions, most of the reactions will only happen down one or two pathways. When you throw a bunch of organic chemicals together, you get many different end products. But the environment will favor certain molecular interactions over others and so the probability distribution will be highly biased. The environment that the chemicals are in acts as a filter for which reaction pathways they are most likely to take. ("evolution" is actually a systems dynamics concept in math, and not just applied to living things. It is used in many other fields, but without the hubbub of biology.)

Incidentally, this is the essence of the flaw in the "statistically impossible" argument re:complex molecular synthesis. The synthesis pathway probability distribution is extremely irregular in the real world, while the assumption in that particular fallacy is that it is perfectly flat. Bad assumption, bad conclusion.

[Aric2000]

LOL, that was very good.

[general_re]

Yes, I am new to FR. I've enjoyed your discussions about evolution and creation for years ...

Interesting - an actual example of the lurkers we all suspect exist, but whom we cannot see.

They're out there... ;)

[js1138]

Nice to see a few constructive posts before the thread succumbs to Lou Gehrig's disease. (you will know it when you see it)

[Kudsman]

May I be the first (36 posts into his/her first thread. Shame on all us.) to say welcome to FR. I'm sure you will enjoy your stay. You will learn that you don't have to agree with everything nor everyone and you will still have fun.

[LiteKeeper]

Just ask yourself one question: where did all of the information in the first cell come from?

The cell with the least genetic information known to man at this time has 482 genes and 580,000 base pairs in the DNA...yet there is not enough genetic information to live on its own - it is a parasite.

It is a fact of life: information cannot come from matter; it is the product of a mental process somewhere.

Information, Science, and Biology

[general_re]

I wouldn't worry too much about that particular affliction. Just bookmark its posts so that you can show them to its descendants when they are old enough to read and comprehend the ass-clownish nature of their ancestor - no doubt, they will be horribly mortified, and all mention of Grampy Lou will be quickly relegated to the family memory-hole...

[StupidQuestions]

"Just ask yourself one question: where did all of the information in the first cell come from?"

That's exactly what I am asking and have been asking for years. I have no answer yet. I know many people here have an answer about which they are certain. I am not so fortunate. You may be right that information cannot come from matter, but in your brain we apparently have the phenomena of matter contemplating matter. I don’t understand how that is possible either.

[LiteKeeper]

Please go back to my earlier post and read the article at the link...it answers a number of your questions. I can provide more links of the same sort if you are really interested!

[bondserv]

What I got from Pasteur was the idea that life is not a Chemical reaction or a group of chemical reactions. There is an animating force which science cannot replicate.

I have yet to see an experiment that can disprove this idea.

In another thread there was a question of at what point is something living considered dead.

It seems to me life becomes animated when electrical activity stimulates chemical reactions. Consistant intake of nutrients (fuel) enables the organism to continue to create the electrical impulses.

If the power supply runs out (starvation) the organism dies. If a critical mechanism (heart attack) in the machine breaks down the machine stops.

When the "power" no longer stimulates the chemistry of the organism, it ceases being alive.

A better question is:
Who has the keys?

[DannyTN]

"If this problem could really be solved in a way that people agreed on, the RNA world would become a fact rather than a speculation."

Interesting. If people agree on it, it "becomes" a "fact", no longer a "speculation". Apparently agreeing makes it so. We can rewrite history. It doesn't matter what really happen. All we have to do is agree and whatever we agree on becomes "facts". History changes.

If we all would agree, Hitler and 911 never happened.

If we all agree StupidQuestions are not really Stupid. Your name will instantly change on this and every other thread. It's a "Fact".

[John Valentine]

Well, the Silurian ring well was pretty convincing to me.

And the Russians have had some interesting data.

And then there is the oil reservoir replenishment phenomenon that conventional petro theory can't explain.

I think that the jury is still hearing evidence in this case, and the prosecution has not rested.

[StupidQuestions]

I read the article at the link you provided. It is not an easy read and I'm sure I'd get more if I read it again. But, I have some problems with it on the first read. The major problem is in accepting the author's basic premise:

"Energy and matter are considered to be basic universal quantities. However, the concept of information has become just as fundamental and far-reaching, justifying its categorisation as the third fundamental quantity."

My problem with that is demonstrated by the author's first theorem:"(1) No information can exist without a code."

Energy and matter seem to exist. Information, needing a code, cannot be declared to be so basic. A water molecule contains information once we codify it: H-O-H. We can identify it's makeup and even learn something about the nature of the co-valent bonds that hold the molecule together. But all of that is information of our making, in a sense.

To say that chemical bonds forged naturally under ultra-violet light are impossible if the arrangement of atoms can be viewed as containing information is not an acceptable proposition to me.

[John Valentine]

Wow! You're in Korea. How is the atmosphere? Tense, expectant, same old same-o?

Here along with 25 million other people. It's tense, but one gets used to it.

[tortoise]

The cell with the least genetic information known to man at this time has 482 genes and 580,000 base pairs in the DNA...yet there is not enough genetic information to live on its own - it is a parasite.

Quite frankly, anything with a smaller genome is at quite a disadvantage; this genome is already pretty damn small. When push comes to shove, critters with bigger genomes have more survival skills. I think it would be more correct to hypothesize that the critter you mentioned above has the smallest surviving genome.

It is a fact of life: information cannot come from matter; it is the product of a mental process somewhere.

That's a nice platitude and all, but it is utterly inconsistent with every rigorous definition of "information" used in math and science. When a raindrop hits the ground information is created, yet I hardly attribute that phenomenon to a mental process. Heck, the sun burning is creating information and an incredible rate, but I don't see any mental processes there either.

[tortoise]

My problem with that is demonstrated by the author's first theorem:"(1) No information can exist without a code."

The problem is more fundamental than what you state. This is not a valid definition of "information" used anywhere in mathematics (or applied from the math in science). Information in the physical realm is roughly defined as the Kolmogorov complexity of differential patterns (in energy fields at the most fundamental level). Needing a "code" immediately triggers the bullshit alarm because information is context-free. Asserting axioms underneath any finite information context is pretty much a fallacy by definition in the mathematics.

That author is peddling snake-oil.

[ladyinred]

I thought UV light was bad for life? Why oh why did I waste all of that money on sun block?